This invention relates to a method for the manufacture of an indium oxide (III) (In.sub.2 O.sub.3) film. The term "indium oxide" applies to both In.sub.2 O and In.sub.2 O.sub.3. For the sake of distinction, therefore, these oxides will be referred to hereinafter as indium oxide (I) and indium oxide (III) respectively.
Films of indium oxide (III) are useful for electroconductive glass articles, oxide film resistors, printed circuits, etc. It has heretofore been known in the art to produce indium oxide (III) films by a procedure of causing indium oxide (III) to be vacuum deposited on the surface of a given substrate (Japanese Patent Publication Sho 49 (1974)-45988. However the nature of the indium oxide (III) which is used directly as the starting material in this method makes it necessary to use an electron-beam heater or other expensive and complicated apparatus capable of generating high-energy electron rays for the vacuum deposition involved.
The inventors searched for a way for overcoming the aforementioned difficulty encountered in the manufacture of indium oxide (III) films. They have, consequently, developed a method which, by use of a much less expensive apparatus, produces an indium oxide (III) film possessing a quality comparable with or better than the quality of indium oxide (III) film manufactured by the conventional electron-beam heater.
An object of the present invention is to provide a method which produces an indium oxide (III) film on a substrate with high efficiency by use of a very simple apparatus.